Is Section 1B at Meadowbrook a raised section or are you even with the stage?

Front Pavilion sections at Meadowbrook are actually below the stage and only rise slightly as you move further away. This can cause issues for smaller fans (as you mentioned) - especially when others are standing.

Photo adapted from Foursquare user Jack B.

The R5 concert has a unique setup where there is no standing Pit and Pavilion sections 1A-1C extend all the way to the stage with Row 1 right up against the stage. Thus, buying tickets in Row 1 will alleviate concerns with seeing around taller fans. If these tickets are out of your price range, keep in mind this particular show is aimed at a younger crowd, so you should expect a fair number of other smaller children who your daughter should be able to see over.

Other seats with more rise are found in Pavilion 3 (sections 3A-3E), though these are much farther away from the stage.